When you work in combinations the first has to either be real or indistinguishable from a real attack from the 's perspective. Attacking in combinations is a key element of in Jiu jitsu. It's unlikely your first attack will work every time on skilled opponents and in the vast majority of cases you'll need to strong moves together so the second, third or fourth gets the break through. When athletes start to attack in it's to subconsciously easy on the first move because you know inside your that you're banking on the second one being the real attack. However, when you do this the opponent will simply not react to the threat of a noncommittal first attack and the whole combination you had mapped out in your head will fail before it even begins. So make sure you put some pep in that opening move – even when you're not expecting it to break through – all the subsequent move depend on it!